This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:                3GPP third generation partnership project        BS base station        COMP coordinated multipoint        CSI channel state information        CSI-RS channel state information-reference signals        CQI channel quality indicator        DL downlink (from base station to user equipment)        DM-RS demodulation reference symbols        eNB E-UTRAN Node B (evolved Node B, also eNodeB)        E-UTRAN evolved UTRAN (LTE)        LTE long term evolution of UTRAN (E-UTRAN)        LTE-A LTE advanced        MCS modulation and coding scheme        MIMO multiple input multiple output        MME mobility management entity        NCE network control element        PDSCH physical downlink shared channel        PMI precoding matrix indicator        PUCCH physical uplink control channel        PUSCH physical uplink shared channel        OFDM orthogonal frequency division multiplexing        OFDMA orthogonal frequency division multiple access        Rel. release        TM transmission mode        TS technical standard        RAT radio access technology        RRH remote radio head        RS reference signal/symbol        RSRP reference symbol received power        RSRP reference symbol received quality        SC-FDMA single carrier, frequency division multiple access        SGW serving gateway        SRS sounding reference symbols        UE user equipment, such as a mobile station, mobile node or mobile terminal        UL uplink (from user equipment to base station)        UTRAN universal terrestrial radio access network        WCDMA wideband code division multiple access        
COordinated MultiPoint (COMP) transmission and reception is one of the investigated technologies in 3GPP LTE-A to enhance specifically the cell-edge data rates in order to create a more uniform data rate experience for the end user over the entire cell area. The COMP techniques involve increased collaboration between different transmission/reception points (e.g., eNodeBs, RRHs, hotspots, home eNodeBs etc.) in DL transmissions to the UE and UL receptions from the UE.
Already in Rel. 10, there has been a related study item in 3GPP, but the study item had been put on hold. The study item was recently restarted in 3GPP in January 2011 according to the study item description. Moreover, different scenarios to be investigated have been agreed to in 3GPP for the study item phase. One of the agreed scenarios (RAN1#63bis meeting, Dublin, January 2011) concentrates on a network with low power RRHs within the macro cell coverage where the transmission/reception points created by the RRHs have the same cell IDs as the macro cell. This situation is denoted therein as “single-cell COMP”.